Equivalent conductance of saturated ${\mathrm{BaSO}}_4$ is 400${\mathrm{ohm}}^{-1} {\mathrm{cm}}^2{\mathrm{equiv}}^{-1}$  and specific conductance is $8\mathrm{x}{10}^{-5} {\mathrm{ohm}}^{-1}, {\mathrm{cm}}^{-1.}$. Hence ${\mathrm{K}}_{\mathrm{sp}} \mathrm{of} {\mathrm{BaSO}}_4$ is